-LRB- CNN -RRB- -- Syria 's embattled government will get at least 10 fighter jets from Russia -- and they want more , Russian state media reports -- moves that come amid rocky diplomatic efforts to peacefully end the Middle East nation 's bloody civil war .

A source involved in Russia 's defense complex told the official Itar-Tass news agency Friday that Russia will sell Syrian President Bashar al-Assad 's government MiG-29 fighter jets to fulfill a `` contract ... concluded long ago . ''

A Syrian delegation in Moscow is pressing for even more jets , with MiG executive Sergei Korotkov telling Russia 's state-run RIA Novosti 's news that his company and these Syrian authorities are talking about the `` details and time frame of a possible contact . ''

Such discussions come on the heels of the European Union 's decision to end its Syrian arms embargo . That move was seen as opening the door for European nations to help rebel fighters militarily , though it may give Russia more wiggle room to back its longtime ally , Assad .

It 's not clear how weapons , fighter jets and ammunition flowing into Syria will affect the fighting there , much less the heretofore unsuccessful attempts to forge a negotiated settlement .

About 80,000 people have been killed since the start of hostilities more than two years ago , U.N. General Assembly President Vuk Jeremic said earlier this month . Another 1.5 million or more people have fled the country .

In addition to the fighter jets , Russia reportedly sold six S-300 air defense systems to Syria under a 2010 contract .

Asked Thursday about these and other arms sales , al-Assad said it is `` not our policy to talk publicly about military issues in terms of what we possess or what we receive . ''

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`` As far as Russia is concerned , the contracts have nothing to do with the crisis , '' he told Hezbollah 's Al-Manar TV , according to a transcript from Syria 's official SANA news service . `` We have negotiated with them on different kinds of weapons for years , and Russia is committed to honoring these contracts . ''

Moscow , however , has said such deliveries would conform with international law and has denied supplying Syria with weapons that can be used against civilians .

U.S. Secretary of State John Kerry described any transfer of S-300s to the region as `` not helpful . ''

`` Whether it 's an old contract or not , it has a profoundly negative impact on the balance of interests and the stability of the region , and it does put Israel at risk , '' he said .

Kerry added that halting the bloodshed peacefully should be everyone 's first priority .

`` The best chance to save Syria -LRB- and -RRB- for a future Syria that represents all Syrian people and moves beyond this massacre , devastation , killing , sectarian violence ... is through a peaceful resolution that comes about in an organized way , '' he said Friday at a joint news conference in Washington with German Foreign Minister Guido Westerwelle .

`` In Geneva , we will test who is serious . Are the Russians serious pushing to that ? I believe they are . -LRB- But -RRB- it is not helpful to have a lot of other ammunition , other supplies overtly going in . ''

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Conference on crisis planned for Switzerland

He was referring to an international conference on the crisis slated for Switzerland . The plans are being worked out , but al-Assad predicted it will take place in June .

`` We have announced a couple of days ago that we agree in principle to attend , '' he said .

But the Syrian leader made clear that his position may change , and Damascus ' delegation may withdraw , if certain conditions are imposed .

`` So the idea of the conference , of a meeting , in principle is a good one , '' he told Al-Manar TV . `` We will have to wait and see . ''

The National Coalition , the main rebel umbrella group , has demanded al-Assad step aside in order for it to take part in the talks , which were originally scheduled for this month .

`` It is difficult to continue when Syrians are constantly being hammered by the Assad regime with the help of outside forces , '' George Sabra , acting chairman of the National Coalition , said in a statement .

He cited the siege of Qusayr and attacks on Eastern Gouta , a suburb of Damascus , as well as what he said was an `` invasion '' by Iranian militia members in support of al-Assad .

Al-Assad said it 's too early to discuss whether or not he 'll run again for president in the 2014 election . He 'd do so if `` there is a need and public desire '' for him to stay on , but wo n't `` if I feel that the Syrian people do not want me to lead them . ''

The Syrian president his only condition is that anything agreed to address the crisis should not be binding until Syrians approve it through a popular referendum .

`` Either side can propose anything , but nothing can be implemented without the approval of the Syrian people . And as long as we are the legitimate representatives of the people , we have nothing to fear , '' the Syrian leader said .

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Opposition group : 50 prisoners executed

All the deals and the talk have done little to change the situation on the ground in Syria .

The killing continued Friday , with the opposition Local Coordination Committees reporting 189 deaths , including six women , five children and 19 who died after being tortured .

There were 74 people killed in Aleppo province , including 50 prisoners who the group said were executed by government forces in Aleppo 's Central Prison , the group said .

In addition , Syrian state-run television have reported that forces loyal to al-Assad killed three Westerners -- an American woman , a Briton and a person whose nationality was not revealed .

The news outlet said Thursday the three had been fighting alongside the rebels and were found with weapons . The report said they were ambushed in their car in the flashpoint province of Idlib in northwestern Syria , where government forces have been battling rebels for control .

TV video showed a bullet-riddled car and three bodies laid out on the ground . It also showed weapons , a computer , a hand-drawn map of a government military facility and a flag belonging to the al Qaeda-affiliated al-Nusra Front .

The United States is aware of the report of the reported killing of the American and is working through the Czech Republic mission in Syria to obtain more information , a State Department official , speaking on condition of anonymity , told CNN .

Citing privacy concerns , the official said , `` We are unable to comment further . ''

Pictures circulating on the Internet show the body of Nicole Lynn Mansfield , 33 , of Flint , Michigan , her father and daughter told CNN on Friday .

The UK Foreign Office confirmed that a British national was among the dead . `` Their family has been informed and we are providing consular assistance , '' it said .

Kerry , the top U.S. diplomat , said that some 1,500 to 2,000 American fighters may be in Syria .

`` It 's hard to get a peg on the exact number , '' he said .

American 's family : She went to Syria to help

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NEW : Russia will send 10 MiG-29 fighter jets , Russian state media reports

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NEW : A Syrian delegation in Moscow is pressing for more fighter jets

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NEW : 189 are reported dead nationwide , an opposition group says

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Syrian president says the balance of power favors his armed forces